Retailers fought the headwinds of two entirely different storms this month, both of them likely to shrink holiday sales. The first storm was natural -- a massive blizzard in the Northeast and parts of the Midwest that kept shoppers at home on Super Saturday. The traffic-measurement company ShopperTrak found that for the full Super Saturday weekend (Dec. 18-20), year-over-year retail sales slipped 2.1 percent, totaling $18.8 billion. %%DynaPub-Enhancement class="enhancement contentType-HTML Content fragmentId-1 payloadId-61603 alignment-right size-small"%%The second storm was financial, a creation of the credit card industry, which cut customer spending limits and rejected more credit card applications than it previously had. The consumer-polling firm America's Research Group expects this tightening of credit could result in $9 billion in lost holiday sales revenue.